CODEWITHSUNDEEP
c++cmakelinkerclang
Li Chen
Li Chen

Reputation: 5280

linker error with cmake and libcxx

Background

llvm, clang, libcxx/libcxxabi are built from source by me. they are located at usr/local.

Minimum source file

//findpath.cpp

#include <iostream>
int main(){
    std::cout << "Hi";
}

CMakeLists.txt

cmake_minimum_required(VERSION 3.6)
set(CMAKE_CXX_COMPILER "clang++")
set(CMAKE_C_COMPILER "clang")

project(FindPath)
add_compile_options("-stdlib=libc++" "-lc++abi" "-v")

add_executable(path findpath.cpp)

With cmake(output linker error)

~/.../findpath/build >>> cmake -DCMAKE_EXPORT_COMPILE_COMMANDS=1 ..                                                                                                ±[●][master]
-- The C compiler identification is Clang 8.0.0
-- The CXX compiler identification is Clang 8.0.0
-- Check for working C compiler: /usr/local/bin/clang
-- Check for working C compiler: /usr/local/bin/clang -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/local/bin/clang++
-- Check for working CXX compiler: /usr/local/bin/clang++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Configuring done
-- Generating done
-- Build files have been written to: /home/firstlove/projects/smalltools/findpath/build
~/.../findpath/build >>> make                                                                                                                                      ±[●][master]
Scanning dependencies of target path
[ 50%] Building CXX object CMakeFiles/path.dir/findpath.cpp.o
clang version 8.0.0 (http://llvm.org/git/clang 55ead9f6f66545bcfda4a0f7e6dd3748a296f826) (https://github.com/llvm-mirror/llvm.git 8d97f0d4be38ebd4b38fe2cff51e0713b3dfba66)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-pc-linux-gnu/8.1.1
Found candidate GCC installation: /usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1
Selected GCC installation: /usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
clang-8: warning: -lc++abi: 'linker' input unused [-Wunused-command-line-argument]
 "/usr/local/bin/clang-8" -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -discard-value-names -main-file-name findpath.cpp -mr
elocation-model static -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column
-info -debugger-tuning=gdb -v -coverage-notes-file /home/firstlove/projects/smalltools/findpath/build/CMakeFiles/path.dir/findpath.cpp.gcno -resource-dir /usr/local/lib/clang/8
.0.0 -internal-isystem /usr/local/bin/../include/c++/v1 -internal-isystem /usr/local/include -internal-isystem /usr/local/lib/clang/8.0.0/include -internal-externc-isystem /inc
lude -internal-externc-isystem /usr/include -fdeprecated-macro -fdebug-compilation-dir /home/firstlove/projects/smalltools/findpath/build -ferror-limit 19 -fmessage-length 176 
-fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -o CMakeFiles/path.dir/findpath.cpp.o -x c++ /home/firstlove/projects/smalltools/
findpath/findpath.cpp -faddrsig
clang -cc1 version 8.0.0 based upon LLVM 8.0.0svn default target x86_64-unknown-linux-gnu
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/bin/../include/c++/v1
 /usr/local/include
 /usr/local/lib/clang/8.0.0/include
 /usr/include
End of search list.
[100%] Linking CXX executable path
CMakeFiles/path.dir/findpath.cpp.o: In function `main':
findpath.cpp:(.text+0xa): undefined reference to `std::__1::cout'
CMakeFiles/path.dir/findpath.cpp.o: In function `std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::__put_character_sequence<char, std::__1::char_traits<cha
r> >(std::__1::basic_ostream<char, std::__1::char_traits<char> >&, char const*, unsigned long)':
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x2f): undefined reference to `std::__1::basic_ostream<char, std::__1::char_traits<char> >::sentry::sentry(std::__1::basic_ostream<char, st
d::__1::char_traits<char> >&)'
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x1be): undefined reference to `std::__1::ios_base::getloc() const'
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x1d4): undefined reference to `std::__1::ctype<char>::id'
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x1d9): undefined reference to `std::__1::locale::use_facet(std::__1::locale::id&) const'
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x235): undefined reference to `std::__1::locale::~locale()'
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x257): undefined reference to `std::__1::locale::~locale()'
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x327): undefined reference to `std::__1::ios_base::clear(unsigned int)'
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x384): undefined reference to `std::__1::basic_ostream<char, std::__1::char_traits<char> >::sentry::~sentry()'
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x3ad): undefined reference to `std::__1::ios_base::__set_badbit_and_consider_rethrow()'
findpath.cpp:(.text._ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEERNS_13basic_ostreamIT_T0_EES7_PKS4_m[_ZNSt3__124__put_character_sequenceIcNS_11char_traitsIcEEEER
NS_13basic_ostreamIT_T0_EES7_PKS4_m]+0x3d8): undefined reference to `std::__1::basic_ostream<char, std::__1::char_traits<char> >::sentry::~sentry()'
CMakeFiles/path.dir/findpath.cpp.o: In function `std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> > std::__1::__pad_and_output<char, std::__1::char_traits<char> 
>(std::__1::ostreambuf_iterator<char, std::__1::char_traits<char> >, char const*, char const*, char const*, std::__1::ios_base&, char)':
findpath.cpp:(.text._ZNSt3__116__pad_and_outputIcNS_11char_traitsIcEEEENS_19ostreambuf_iteratorIT_T0_EES6_PKS4_S8_S8_RNS_8ios_baseES4_[_ZNSt3__116__pad_and_outputIcNS_11char_tr
aitsIcEEEENS_19ostreambuf_iteratorIT_T0_EES6_PKS4_S8_S8_RNS_8ios_baseES4_]+0x219): undefined reference to `std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::a
llocator<char> >::__init(unsigned long, char)'
findpath.cpp:(.text._ZNSt3__116__pad_and_outputIcNS_11char_traitsIcEEEENS_19ostreambuf_iteratorIT_T0_EES6_PKS4_S8_S8_RNS_8ios_baseES4_[_ZNSt3__116__pad_and_outputIcNS_11char_tr
aitsIcEEEENS_19ostreambuf_iteratorIT_T0_EES6_PKS4_S8_S8_RNS_8ios_baseES4_]+0x388): undefined reference to `std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::a
llocator<char> >::~basic_string()'
findpath.cpp:(.text._ZNSt3__116__pad_and_outputIcNS_11char_traitsIcEEEENS_19ostreambuf_iteratorIT_T0_EES6_PKS4_S8_S8_RNS_8ios_baseES4_[_ZNSt3__116__pad_and_outputIcNS_11char_tr
aitsIcEEEENS_19ostreambuf_iteratorIT_T0_EES6_PKS4_S8_S8_RNS_8ios_baseES4_]+0x3a3): undefined reference to `std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::a
llocator<char> >::~basic_string()'
clang-8: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [CMakeFiles/path.dir/build.make:84: path] Error 1
make[1]: *** [CMakeFiles/Makefile2:73: CMakeFiles/path.dir/all] Error 2
make: *** [Makefile:84: all] Error 2

Without cmake(no link error): clang++ -stdlib=libc++ -lc++abi -std=c++17 -v findpath.cpp

~/.../smalltools/findpath >>> clang++ -stdlib=libc++ -lc++abi -std=c++17 -v findpath.cpp                                                                           ±[●][master]
clang version 8.0.0 (http://llvm.org/git/clang 55ead9f6f66545bcfda4a0f7e6dd3748a296f826) (https://github.com/llvm-mirror/llvm.git 8d97f0d4be38ebd4b38fe2cff51e0713b3dfba66)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /usr/local/bin
Found candidate GCC installation: /usr/lib/gcc/x86_64-pc-linux-gnu/8.1.1
Found candidate GCC installation: /usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1
Selected GCC installation: /usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
 "/usr/local/bin/clang-8" -cc1 -triple x86_64-unknown-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -discard-value-names -main-file-name findpath.cpp -mr
elocation-model static -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 -dwarf-column
-info -debugger-tuning=gdb -v -resource-dir /usr/local/lib/clang/8.0.0 -internal-isystem /usr/local/bin/../include/c++/v1 -internal-isystem /usr/local/include -internal-isystem
 /usr/local/lib/clang/8.0.0/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -std=c++17 -fdeprecated-macro -fdebug-compilation-dir /home/firstl
ove/projects/smalltools/findpath -ferror-limit 19 -fmessage-length 176 -fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -fcolor-diagnostics -o /tmp/fi
ndpath-7dd1ae.o -x c++ findpath.cpp -faddrsig
clang -cc1 version 8.0.0 based upon LLVM 8.0.0svn default target x86_64-unknown-linux-gnu
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/local/bin/../include/c++/v1
 /usr/local/include
 /usr/local/lib/clang/8.0.0/include
 /usr/include
End of search list.
 "/usr/bin/ld" --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o a.out /usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1/../../../../lib64/crt1.o /usr/lib64/gc
c/x86_64-pc-linux-gnu/8.1.1/../../../../lib64/crti.o /usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1/crtbegin.o -L/usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1 -L/usr/lib64/gcc/x86_64-pc-l
inux-gnu/8.1.1/../../../../lib64 -L/lib/../lib64 -L/usr/lib/../lib64 -L/usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1/../../.. -L/usr/local/bin/../lib -L/lib -L/usr/lib -lc++abi /tmp
/findpath-7dd1ae.o -lc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1/crtend.o /usr/lib64/gcc/x86_64-pc-linux-gnu/8.1.1/../../../../lib64/crtn.o

But from /usr/bin/ld, it seems use gcc to link?

I have google much, but nothing useful found. If any more information needed, please tell me, thanks in advance.

Update

Except for telling me the linker is gnu's ld, other error messages are the same.

Then I give llvm's lld a try,

set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -fuse-ld=lld -stdlib=libc++ -lc++abi")

/usr/bin/cmake -H/home/firstlove/projects/smallProjects/smalltools/findpath -B/home/firstlove/projects/smallProjects/smalltools/findpath/build --check-build-system CMakeFiles/M
akefile.cmake 0                                                                                                                                                                
/usr/bin/cmake -E cmake_progress_start /home/firstlove/projects/smallProjects/smalltools/findpath/build/CMakeFiles /home/firstlove/projects/smallProjects/smalltools/findpath/bu
ild/CMakeFiles/progress.marks                                                                                                                                                  
make -f CMakeFiles/Makefile2 all
make[1]: Entering directory '/home/firstlove/projects/smallProjects/smalltools/findpath/build'
make -f CMakeFiles/path.dir/build.make CMakeFiles/path.dir/depend
make[2]: Entering directory '/home/firstlove/projects/smallProjects/smalltools/findpath/build'
cd /home/firstlove/projects/smallProjects/smalltools/findpath/build && /usr/bin/cmake -E cmake_depends "Unix Makefiles" /home/firstlove/projects/smallProjects/smalltools/findpa
th /home/firstlove/projects/smallProjects/smalltools/findpath /home/firstlove/projects/smallProjects/smalltools/findpath/build /home/firstlove/projects/smallProjects/smalltools
/findpath/build /home/firstlove/projects/smallProjects/smalltools/findpath/build/CMakeFiles/path.dir/DependInfo.cmake --color=                                                 
make[2]: Leaving directory '/home/firstlove/projects/smallProjects/smalltools/findpath/build'
make -f CMakeFiles/path.dir/build.make CMakeFiles/path.dir/build
make[2]: Entering directory '/home/firstlove/projects/smallProjects/smalltools/findpath/build'
[ 50%] Linking CXX executable path
/usr/bin/cmake -E cmake_link_script CMakeFiles/path.dir/link.txt --verbose=1
clang++     -fuse-ld=lld -stdlib=libc++ -lc++abi CMakeFiles/path.dir/findpath.cpp.o  -o path 
/usr/bin/ld.lld: error: undefined symbol: std::cout
>>> referenced by findpath.cpp
>>>               CMakeFiles/path.dir/findpath.cpp.o:(main)

/usr/bin/ld.lld: error: undefined symbol: std::basic_ostream<char, std::char_traits<char> >& std::operator<<<std::char_traits<char> >(std::basic_ostream<char, std::char_traits<
char> >&, char const*)                                                                                                                                                         
>>> referenced by findpath.cpp
>>>               CMakeFiles/path.dir/findpath.cpp.o:(main)

/usr/bin/ld.lld: error: undefined symbol: std::ios_base::Init::Init()
>>> referenced by findpath.cpp
>>>               CMakeFiles/path.dir/findpath.cpp.o:(__cxx_global_var_init)

/usr/bin/ld.lld: error: undefined symbol: std::ios_base::Init::~Init()
>>> referenced by findpath.cpp
>>>               CMakeFiles/path.dir/findpath.cpp.o:(__cxx_global_var_init)
clang-6.0: error: linker command failed with exit code 1 (use -v to see invocation)
make[2]: *** [CMakeFiles/path.dir/build.make:84: path] Error 1
make[2]: Leaving directory '/home/firstlove/projects/smallProjects/smalltools/findpath/build'
make[1]: *** [CMakeFiles/Makefile2:68: CMakeFiles/path.dir/all] Error 2
make[1]: Leaving directory '/home/firstlove/projects/smallProjects/smalltools/findpath/build'
make: *** [Makefile:84: all] Error 2

Oops, similar linker error...

Again, without cmake, it works fine:

~/.../smalltools/findpath >>> clang++ -stdlib=libc++ -lc++abi -std=c++17 -v -fuse-ld=lld findpath.cpp                                                            ±[A1●][master]
clang version 6.0.1 (tags/RELEASE_601/final)
Target: x86_64-pc-linux-gnu
Thread model: posix
InstalledDir: /usr/bin
Found candidate GCC installation: /usr/bin/../lib/gcc/x86_64-pc-linux-gnu/8.2.0
Found candidate GCC installation: /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/8.2.0
Found candidate GCC installation: /usr/lib/gcc/x86_64-pc-linux-gnu/8.2.0
Found candidate GCC installation: /usr/lib64/gcc/x86_64-pc-linux-gnu/8.2.0
Selected GCC installation: /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/8.2.0
Candidate multilib: .;@m64
Candidate multilib: 32;@m32
Selected multilib: .;@m64
 "/usr/bin/clang-6.0" -cc1 -triple x86_64-pc-linux-gnu -emit-obj -mrelax-all -disable-free -disable-llvm-verifier -discard-value-names -main-file-name findpath.cpp -mrelocation
-model pic -pic-level 2 -pic-is-pie -mthread-model posix -mdisable-fp-elim -fmath-errno -masm-verbose -mconstructor-aliases -munwind-tables -fuse-init-array -target-cpu x86-64 
-dwarf-column-info -debugger-tuning=gdb -v -resource-dir /usr/lib/clang/6.0.1 -internal-isystem /usr/bin/../include/c++/v1 -internal-isystem /usr/local/include -internal-isyste
m /usr/lib/clang/6.0.1/include -internal-externc-isystem /include -internal-externc-isystem /usr/include -std=c++17 -fdeprecated-macro -fdebug-compilation-dir /home/firstlove/p
rojects/smallProjects/smalltools/findpath -ferror-limit 19 -fmessage-length 176 -stack-protector 2 -fobjc-runtime=gcc -fcxx-exceptions -fexceptions -fdiagnostics-show-option -f
color-diagnostics -o /tmp/findpath-671136.o -x c++ findpath.cpp                                                                                                                
clang -cc1 version 6.0.1 based upon LLVM 6.0.1 default target x86_64-pc-linux-gnu
ignoring nonexistent directory "/include"
#include "..." search starts here:
#include <...> search starts here:
 /usr/bin/../include/c++/v1
 /usr/local/include
 /usr/lib/clang/6.0.1/include
 /usr/include
End of search list.
 "/usr/bin/ld.lld" -pie --eh-frame-hdr -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 -o a.out /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/8.2.0/../../../../lib64/Scrt
1.o /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/8.2.0/../../../../lib64/crti.o /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/8.2.0/crtbeginS.o -L/usr/bin/../lib64/gcc/x86_64-pc-linux
-gnu/8.2.0 -L/usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/8.2.0/../../../../lib64 -L/usr/bin/../lib64 -L/lib/../lib64 -L/usr/lib/../lib64 -L/usr/bin/../lib64/gcc/x86_64-pc-linux-g
nu/8.2.0/../../.. -L/usr/bin/../lib -L/lib -L/usr/lib -lc++abi /tmp/findpath-671136.o -lc++ -lm -lgcc_s -lgcc -lc -lgcc_s -lgcc /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/8.2.0/
crtendS.o /usr/bin/../lib64/gcc/x86_64-pc-linux-gnu/8.2.0/../../../../lib64/crtn.o                                                                                             
~/.../smalltools/findpath >>>                                                                                                                                   ±[A1●●][master]
~/.../smalltools/findpath >>> ./a.out                                                                                                                           ±[A1●●][master]
Hi%

Upvotes: 2

Views: 4963

Answers (1)

Li Chen
Li Chen

Reputation: 5280

@jonathon solve this problem in my this question.

The solutsion is setting both compiler and linker options so it can find libc++:

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -stdlib=libc++ -v")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -stdlib=libc++ -lc++abi")

Upvotes: 4

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